Profile cutting apparatus have been used for some years to cut a variety of materials such as steel, aluminium, glass, marble, plastics, rubber, cork and wood. Examples of profile cutting apparatus include waterjet cutting machines, plasma cutting machines and laser cutting machines.
Taking waterjet cutting machines as an example, the work piece is placed over a shallow tank of water and a cutting head expelling a cutting jet is accurately displaced across the work piece to complete the desired cut. The cutting action is carried out by the combination of a very high pressure jet (up to 60,000 psi) of water entrained with fine particles of abrasive material, usually sand, that causes the cutting action. The water and sand that exit the cutting head are collected beneath the work piece in the tank.
The abrasive material is usually particles of silica sand, cast iron grit, powdered garnet or alumina. The particle size of the abrasive material is usually between 60 and 150 mesh.
The high pressure water jet is usually passed through a venturi that is connected to a vacuum line that is in turn connected to an abrasive metering assembly that meters dry abrasive delivered from a hopper and carried by the vacuum to the cutting head at a desired flow rate that is often between about 100 to 700 grams per minute.
This cutting technique is very powerful and can cut through stainless steel as thick as 100 mm or 4 inches. The cutting process can also be extremely accurate with tolerances of plus or minus 0.1 mm or 0.004 inches. The process is clean, fast and reliable. Nevertheless, the resulting cutting path is limited to the movement parameters of the apparatus and certain cutting paths of varying degrees of sophistication are unable to be achieved with known waterjet cutting apparatus.
There is therefore a need to improve the performance and versatility of profile cutting apparatus such as waterjet cutting apparatus.